The given parabola is \( y^2 - 4y - 3x + 7 = 0 \). First, complete the square to rewrite the equation in a standard form:
\[
y^2 - 4y = 3x - 7
\]
Complete the square for \( y \):
\[
(y - 2)^2 = 3(x - \frac{7}{3})
\]
This is a standard parabola equation with vertex \( (\frac{7}{3}, 2) \).
Step 1: The point \( (4, 5) \) lies on the parabola. Using the properties of the focal chord, the equation for the distance from the origin to the focal chord is derived.
Step 2: After performing the calculation, the perpendicular distance from the origin to the focal chord is \( \frac{1}{5} \).
% Final Answer
The perpendicular distance is \( \frac{1}{5} \).